Theory of Enthalpy of Mixing in Reactive Charge Asymmetrical Molten Salt Systems. Part II. Ternary Solutions

1972 ◽  
Vol 50 (9) ◽  
pp. 1345-1352
Author(s):  
S. N. Flengas ◽  
J. M. Skeaff
Keyword(s):  
Ternary System ◽  
Molten Salt ◽  
Binary Systems ◽  
Enthalpy Of Mixing ◽  
Complex Species ◽  
Enthalpies Of Mixing ◽  
Ternary Solutions ◽  
Products Of Reaction ◽  
Molten Salt System ◽  
Salt Systems

The enthalpies of mixing for a reacting charge asymmetrical ternary molten salt system have been calculated on the basis of an extension of a previously developed model for binary systems. The enthalpy of mixing is considered to consist of a reaction term and a mixing term; the former results from the formation of the tetrahedrally coordinated complex species [Formula: see text] and the latter from the mixing of the products of reaction according to quasichemical theory modified to account for charge asymmetry.The ternary model enables the prediction of the integral enthalpies from a knowledge of the interaction parameters determined for the two charge asymmetrical binary systems. The calculations are compared with experimentally measured integral enthalpies of mixing in the ternary system MnCl2–NaCl–CsCl, and shown to give accurate predictions of the behaviour of the system.

Theory of Enthalpy of Mixing in Reactive Charge Asymmetrical Molten Salt Systems. Part I. Binary Solutions

1971 ◽  
Vol 49 (24) ◽  
pp. 3971-3985 ◽  
Author(s):  
S. N. Flengas ◽  
A. S. Kucharski
Keyword(s):  
Molten Salt ◽  
Metal Cations ◽  
Enthalpy Of Mixing ◽  
Chloride Ions ◽  
Central Metal ◽  
Mixing Process ◽  
Alkali Metal Cations ◽  
Complex Species ◽  
The Difference ◽  
Salt Systems

The enthalpies of mixing for the charge asymmetrical molten salt systems; MnCl2-ACl, FeCl2–ACl, CoCl2–ACl, NiCl2–ACl, MgCl2–ACl, and CdCl2–ACl (where A represents Li, Na, K, Rb, and Cs) have been calculated by separating the mixing process into two parts. One part of enthalpy of mixing results from the "reaction" to form a tetrahedral complex, MCl42−, and another part of the enthalpy of mixing arises from the "mixing" of the complexed species with the remaining free components. The "complex" species are treated as orderly configurations defined by shorter anion to cation distances within which the central metal cation interacts with the surrounding other metal cations through bridging chloride ions. The model takes into account the difference in the coordination number of the mono- and divalent components. The interaction parameters are shown to depend upon the radii of the alkali metal cations.

scholarly journals MODELING OF THERMOCHEMICAL PROPERTIES AND GLASSFORMING TENDENCY OF THE MELTS OF TERNARY Mn–Al–Gd SYSTEM

2018 ◽  
pp. 46-50
Author(s):  
N. Kotova ◽  
N. Golovata ◽  
N. Usenko
Keyword(s):  
Ternary System ◽  
Binary Systems ◽  
Hard Spheres ◽  
Regular Solution Model ◽  
Ternary Systems ◽  
Ternary Alloys ◽  
Liquid Alloys ◽  
Thermochemical Properties ◽  
Ternary Compounds ◽  
Enthalpies Of Mixing

In the present work, the enthalpies of mixing of liquid alloys of the ternary Mn-Al-Gd system have been calculated using the regular solution model by the Redlich-Kister-Muggianu formula. Also a comparison was made of calculated values of enthalpies of mixing in this system with the experimentally determined thermochemical properties of liquid alloys of the Mn-In-Gd ternary system obtained previously. In general, we estimate that the values of the enthalpies of mixing in the Mn-Al-Gd ternary system should be more exothermic than in the Mn–In-Gd one. This fact can be explained taking into consideration the main features of the component interaction in the boundary binary systems, namely, such important characteristics as electronegativity of the components, their electron work functions and a large difference in size of atoms. It can be concluded that it is the binary Mn–Al system that makes a significant contribution to the formation energy of ternary alloys. An imaginary line drawn through the points of maximum curvature of the isoenthalpic lines is considerably shifted towards the binary Mn–Al boundary, thus expanding significantly the region of rather exothermic enthalpies of mixing in the corresponding ternary system. For the two indicated ternary systems the size mismatch entropy has been calculated within the framework of hard spheres model and the Sσ/kB parameter has been determined. On the basis of the comprehensive analysis carried out, the criteria for the probability of occurrence of regions of easy amorphization in these ternary systems are proposed. The determination of the topology of the mixing enthalpy surface and the Sσ/kB parameter for the melts of studied ternary systems together with the data on binary and ternary compounds existing in these systems allowed to reasonably assume the concentration regions where the investigated ternary alloys have tendency for easy amorphization while rapid cooling of the melt. The simultaneous realization of the following three conditions was taken as a criterion for the possible existence of a region of easy amorphization: the absolute value of the enthalpies of mixing is at least 6 kJ/mol, the Sσ/kB parameter is not less than 0.3–0.4 and a certain distance from the concentration region corresponding to the exact composition of binary or ternary compounds.

Enthalpies of mixing in binary Cu–Eu and ternary Al–Cu–Eu liquid alloys

2020 ◽  
Vol 111 (4) ◽  
pp. 273-282
Author(s):  
Natalia Usenko ◽  
Michael Ivanov ◽  
Natalia Kotova
Keyword(s):  
Ternary System ◽  
Enthalpy Of Mixing ◽  
Integral Enthalpy ◽  
Liquid Alloys ◽  
Temperature Range ◽  
Enthalpies Of Mixing ◽  
Minimum Value ◽  
Isoperibolic Calorimetry ◽  
Wide Range ◽  
Binary Constituent

Abstract The enthalpies of mixing in liquid alloys of the binary Cu-Eu and ternary Al-Cu-Eu systems were determined over a wide range of compositions by means of isoperibolic calorimetry in the temperature range 1 300 - 1450 K. The enthalpies of mixing in the Cu-Eu system demonstrate small exothermic effects (ΔHmin = -4.1 ± 0.5 kJ · mol-1at xCu = 0.70). The measurements for the liquid ternary Al- Cu-Eu alloys were performed along five sections (xCu/ xEu = 0.70/0.30; 0.50/0.50 and 0.27/0.73 for xAl changed from 0 up to 0.30 and xAl/xEu = 0.20/0.80 and 0.47/0.53 for xCu changed from 0 up to 0.30). The enthalpies of mixing in the ternary system were found to be exothermic and increasing in absolute values from the Al corner towards the Al0.40Cu0.60-Al0.60Eu0.40section and from the constituent binary Cu-Eu system towards the same section. The minimum value of the integral enthalpy of mixing is expected in the vicinity of the Al0.6Eu0.4composition of the binary constituent Al-Eu system (about -23.00 kJ · mol-1).

scholarly journals Thermodynamic properties of the NiCl2–CoCl2–KCl system

1995 ◽  
Vol 73 (10) ◽  
pp. 1596-1599 ◽  
Author(s):  
Peter J. Tumidajski ◽  
Christopher A. Pickles
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Molten Salt ◽  
Activity Coefficients ◽  
Polynomial Equation ◽  
Nickel Chloride ◽  
Ideal Solution ◽  
Complex Species ◽  
Ternary Solutions ◽  
Ideal System

The thermodynamic behavior of NiCl2 in NiCl2–CoCl2–KCl ternary solutions was investigated using formation cells of the type, (−) Ni/NiCl2–CoCl2–KCl/C, Cl2(gas, 1 atm)(+). The values of the NiCl2 activity coefficients indicate a non-ideal system consonant with the formation of complex species. The NiCl2 activity coefficients at 1000 K were fitted to the polynomial equation,[Formula: see text]where[Formula: see text]The experimental data were limited to the ranges 0 ≤ t ≤ 0.80 and 0.10 ≤ y ≤ 0.5. Keywords: molten salt, thermodynamic properties, nickel chloride, non-ideal solution, complex species.

Calorimetric Investigation of MCI-EuCI2 Melts (M = Na, K, Rb)

2001 ◽  
Vol 56 (9-10) ◽  
pp. 653-657
Author(s):  
F. Da Silva ◽  
L. Rycerz ◽  
M. Gaune-Escard
Keyword(s):  
Least Squares ◽  
Interaction Parameter ◽  
Atmospheric Pressure ◽  
Binary Systems ◽  
Composition Range ◽  
Enthalpy Of Mixing ◽  
Mixing Enthalpy ◽  
Calorimetric Investigation ◽  
Direct Calorimetry ◽  
Enthalpies Of Mixing

Abstract The molar enthalpies of mixing (ΔmixHm) of MCl-EuCl2 (M = Na, K, Rb) liquid binary systems were measured at 1138 K over the whole composition range by direct calorimetry. A Calvet type calorimeter was used, and mixing of the two liquid components was achieved by the ampoule break-off technique under argon at atmospheric pressure. The enthalpy of mixing of these systems is negative over the whole composition range with a minimum of approximately -0.5, -3.5 and -4.5 kJ mol-1 for M = Na, K, Rb, respectively. The least-squares coefficients A, B, C in the equation A (kJ mol-1) = A + B x + C x2, where λ is an interaction parameter, are reported. From the trend observed in these MCl-EuCl2 systems it was possible to estimate the mixing enthalpy of the CsCl-EuCl2 system.

Molten salt mixtures. XI. Integral and partial molar volumes in the molten salt systems PbCl2 + NaCl, PbCl2 + RbCl, PbCl2 + CsCl, CdCl2 + RbCl, and CdCl2 + CsCl

1966 ◽  
Vol 19 (9) ◽  
pp. 1591 ◽  
Author(s):  
H Bloom ◽  
PWD Boyd ◽  
JL Laver ◽  
J Wong
Keyword(s):  
Molten Salt ◽  
Molar Volume ◽  
Partial Molar Volume ◽  
Binary Systems ◽  
Partial Molar Volumes ◽  
Complex Ions ◽  
Molar Volumes ◽  
Temperature Range ◽  
Salt Mixtures ◽  
Salt Systems

The densities of molten PbCl2, CsCl, and RbCl and of the molten salt systems PbCl2 + NaCl, PbCl2 + RbCl, PbCl2 + CsCl, CdCl2 + RbCl, and CdCl, + CsCl have been measured to an accuracy of �0.1% by an Archimedean method over a considerable temperature range. Integral and partial molar volume isotherms have been constructed for the above binary systems and are interpreted to show that complex ions are formed in all but the PbCl2+NaCl system.

Thermodynamic treatment of multicomponent fused salt solutions: common anion reactive systems approximation

1991 ◽  
Vol 69 (5) ◽  
pp. 870-883 ◽  
Author(s):  
S. N. Flengas
Keyword(s):  
Molten Salt ◽  
Binary Systems ◽  
Reactive Systems ◽  
Thermodynamic Cycle ◽  
Ternary Systems ◽  
Salt Solutions ◽  
Partial Molar Property ◽  
Salt Systems ◽  
Common Anion ◽  
Fused Salt

From a modified F.F.G. (1) thermodynamic cycle, equations have been developed from which the molar and partial molar excess thermodynamic properties of j-component molten salt solutions may be predicted from binary data.The theory is applicable to reactive molten salt systems and particularly to charge asymmetric fused salt solutions with common anions.It is shown that for a system having j + 1 components, such as [Formula: see text], any molar or partial molar property of mixing for MXq, may be calculated from available data on corresponding j-binary systems, such as MXq–AX, MXq–BX, and [Formula: see text].The equations are of the general form,[Formula: see text]The latter is applicable only when the multicomponent and the binary solutions have the same MXq content and same temperature.The theoretical expressions have been found to predict quite well available data on ternary and quarternary systems. New composition parameters for expressing the compositions in quarternary and quinary systems have been established. Key words: molten salt solutions, multicomponent systems, ternary systems, quarternary systems, quinary systems.

Thermodynamic rationalization of molten-salt clectrodeposition in oxide-based systems

1989 ◽  
Vol 4 (6) ◽  
pp. 1495-1504 ◽  
Author(s):  
S. Crouch-Baker ◽  
R. A. Huggins
Keyword(s):  
Phase Diagram ◽  
Thermodynamic Properties ◽  
Molten Salt ◽  
Salt System ◽  
Single Crystalline ◽  
Crystalline Materials ◽  
Electrodeposition Process ◽  
Isothermal Phase Diagram ◽  
Molten Salt System ◽  
Salt Systems

Electrodeposition from molten-salt systems has been studied extensively as a method of producing both polycrystalline and single-crystalline materials. In this work, the thermodynamic aspects of the electrodeposition process are examined in a number of cases in which the molten-salt system behaves effectively as an oxygen-transporting medium, with particular reference to the thermodynamic properties of the melt. It is demonstrated how information gained from the construction of the appropriate isothermal phase diagram may be used to control and/or rationalize the behavior found in a given melt system on electrolysis.

scholarly journals MODELING OF THERMODYNAMIC PROPERTIES OF THE MELTS OF TERNARY Ge-Mn-Gd SYSTEM

2019 ◽  
pp. 18-22
Author(s):  
N. Golovata ◽  
N. Kotova ◽  
N. Usenko
Keyword(s):  
Thermodynamic Properties ◽  
Gibbs Energy ◽  
Ternary System ◽  
Binary Systems ◽  
Thermodynamic Characteristics ◽  
Published Data ◽  
Liquid Alloys ◽  
Model Calculations ◽  
Enthalpies Of Mixing ◽  
Gibbs Energies

In the present work, the Gibbs energies of mixing of liquid alloys of the Ge-Mn-Gd ternary system were determined, which was made on the basis of an analysis of published data on the thermodynamic properties of liquid alloys of boundary binary systems that form the ternary Ge-Mn-Gd, as well as on the basis of the model calculations in these binary systems. To determine the activities of the components, the Gibbs energies of mixing, and the enthalpies of mixing of liquid alloys of the Ge-Mn(Gd) systems, for which alloying process is accompanied by significant heat release, an ideal associated solution model was applied. For the melts of the Mn-Gd system, which are characterized by rather insignificant exothermic effects, a model of regular solutions was used. The surface of the Gibbs energy of mixing for the alloys of the Ge-Mn-Gd ternary system has been determined on the basis of the concentration dependences of the Gibbs energies of mixing obtained for constituent binary systems under the assumption of additivity of pair interactions using the Redlich-Kister-Muggianu method. The obtained topology of the Gibbs energy isolines projections is compared with the thermochemical properties of liquid alloys of this system that we have determined earlier. A comparative analysis of the topology of these surfaces in the Ge-Mn-Gd system led to the conclusion that the surfaces of ΔG and ΔmH monotonically decrease from the manganese-rich angle of the diagram towards the Ge-Gd side of the concentration triangle. The minimum value of the thermodynamic characteristics of mixing of the ternary liquid alloys corresponds to the composition, which coincides with the composition of the most stable intermetallic compound in the Ge-Gd system. From the course of isolines of free energies and integral enthalpies of mixing, one can also conclude about the influence of a short-range order, existed in the Ge-Mn system near the composition with a mole fraction of mangan greater than 0.7, on the properties of ternary alloys in the vicinity of this composition. Thus, the topology of isolines and the large exothermic values of the obtained thermodynamic properties allow us to make a reasonable conclusion that the strong interaction between unlike components inherent in the Ge-Gd system in the solid state is also maintained for liquid alloys of the Ge-Mn-Gd system.

Exzeßenthalpien und Solvatationsverhalten der Systeme LiBr/Methanol, ZnBr2/Methanol und LiBr/ZnBr2/Methanol

1982 ◽  
Vol 37 (3) ◽  
pp. 224-231
Author(s):  
M. Christahl ◽  
J. Thönnissen
Keyword(s):  
Experimental Data ◽  
Ternary System ◽  
Coordination Number ◽  
Binary Systems ◽  
Excess Enthalpy ◽  
Enthalpies Of Solution ◽  
Solvation Number ◽  
Enthalpies Of Mixing ◽  
Mathematical Approximation

Abstract For the binary systems Li Br/methanol and Zn Br 2/methanol as well as for the ternary system Li Br/Zn Br 2/methanol the integral enthalpies of mixing are experimentally determined. The mixing of Li Br and methanol is more exothermic than in the case of Zn Br 2. The excess enthalpy is largest for the ternary system. From the mathematical approximation of experimental data the differential enthalpies of solution and of dilution are obtained. In the discussion it is concluded that in diluted solutions the salts are surrounded by a strongly coordinated inner solvation sphere (coordination number N = 4) and a less coordinated outer solvation sphere (N = 6) resulting in a total solvation number of N = 10.

Sign in / Sign up

Export Citation Format

Share Document